• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_3
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• pp.113-119
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• 2001

Surface sediments(0~5 cm) were sampled from 22 stations in Ulsan Bay, one of the most highly industrialized regions in Korea, in November 2000. The sediment samples were analyzed for their polycyclic aromatic hydrocarbon(PAH) content using a gas chromatography coupled to a mass spectrometer detector(GC/MSD). The total PAH concentrations in the sediments varied from 14 to 7108 ng/g dry weight with a mean value of 1052 ng/g dry weight. The level of carcinogenic PAHs ranged from 6 to 2396 ng/g dry weight with a mean value of 433 ng/g dry weight. The highest PAH concentrations in the sediments from Ulsan Bay were found at Station U8, whereas the lowest levels were observed at Stations U2 and U 17. The PAH distribution exhibited a decreasing gradient from the inner basin to the outer bay. The predominant contributors to the aromatic ring groups of the 16 PAHs were four- and five-ring groups, such as fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzor[b]fluoranthene, benzor[k]fluoranthene and benzo[a]pyrene, while two- and three-ring aromatics, like naphthalene, acenapthylene, acenaphthene, fluorene, phenanthrene and anthracene, only exhibited a low concentration. The molecular indices for phenanthrene/anthracene and fluoranthen/pyrene were used to Identify the origin of the PAH contamination in the sediments. The results indicated that the PAH contamination in Ulsan Bay was mostly Pyrolytic in origin with a Petrogenic input adjacent to Ulsan and Jangsuengpo harbor.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.531-538
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• 2013

A mass balance method established in this laboratory was applied to determine the purity of an endosulfan-II pure substance. Gas chromatography-flame ionization detector (GC-FID) was used to measure organic impurities. Total of 10 structurally related organic impurities were detected by GC-FID in the material. Water content was determined to be 0.187% by Karl-Fischer (K-F) coulometry with an oven-drying method. Non-volatile residual impurities was not detected by Thermal gravimetric analysis (TGA) within the detection limit of 0.04% (0.7 ${\mu}g$ in absolute amount). Residual solvents within the substance were determined to be 0.007% in the Endosulfan-II pure substance by running GC-FID after dissolving it with two solvents. The purity of the endosulfan-II was finally assigned to be ($99.17{\pm}0.14$)%. Details of the mass balance method including interpretation and evaluating uncertainties of results from each individual methods and the finally assayed purity were also described.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.169-175
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• 2006

Potentiometric biosensor using flow injection analysis system was developed to determine citrate concentration in foods. Biosensor system consisted of sample injector, peristaltic pump, enzyme reactor, carbonate ion selective solid-state electrode, reference electrode, detector, and recorder. Enzyme reactor was prepared with immobilized citrate lyase and oxaloacetate decarboxylase. Carbonate ions produced through enzyme reactions of citrate were potentiometrically detected by ion selective electrode. Optimum conditions for biosensor system were investigated. Interference effect of major sugars and organic acids was less than 5% on citrate biosensor system. Citrate concentrations in fruit juices were determined by biosensor and gas chromatography. No significant difference was observed between two analytical methods. Results indicate citrate biosensor is useful in determining citrate concentration in foods.

• Journal of Preventive Medicine and Public Health
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• v.27 no.3 s.47
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• pp.569-579
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• 1994

The genetically determined ability to metabolize debrisoquine (DBR) is related to risk of lung cancer and DBR hydroxylation exhibits wide inter-individual variation. In this study, 100 korean adults were tested for their ability to metabolize DBR. The DBR metabolic phenotype were determined by metabolic ratio (MR, DBR / 4-HDBR) which is the percent dose excreted as unchanged DBR divided by the percent dose excreted as 4-hydroxyebrisoquine(4-HDBR) in a aliquot of an eight hour urine sample, after 10mg DBR test dose administration. Analysis was performed on a capillary gas chromatograph fitted with electron capture detector. The results were as follows; 1 Geometric mean of DBR MR was 0.32 in male,0.27 in female,0.30 in total and the distribution of log (MR) was seemed to follow normal distribution. 2. Metabolic ratio of DBR was higher in non-smoker and non-drinker than in smoker and drinker without any statistically significant difference. 3. None of personal factors was significantly related to DBR MR except age. 4. The DBR metabolic phenotype was extensive metabolizer(EM) 93, intermediate metabolizer(IM) 7 by traditional method and EM 98, IM 3 by Caporaso's method. The poor metabolizer (PM) phenotype was not found by either method. 5. Maximal expected PM phenotype was 0.36% by traditional method and 0.04% by Caporaso's method.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.4
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• pp.454-459
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• 2011

In this study, the recovery rate of Tedlar bag (T) sampler was investigated in comparison to polyester aluminum bag (P) sampler. To derive the comparative data sets for the relative performance between different samplers, a series of calibration experiments were performed by using 1 ppb standard of four offensive reduced sulfur compounds (RSC) odorants ($H_2S$, $CH_3SH$, DMS, and DMDS) along with $SO_2$ and $CS_2$. All the analysis was made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). The measurement data were obtained by loading gaseous standards (1 ppb) at 3 injection volumes (250, 500 and 1,000 mL) at three intervals (0, 24 and 72 hrs). The recovery rates (RR) of P sampler were computed against the slope values of T sampler. According to our analysis, P sampler exhibits slightly enhanced loss relative to T, especially with light RSCs ($H_2S$ and $CH_3SH$). At day 0, RR for the two were 88 and 85%, respectively. Such reduction proceeded rather rapidly in the case of $H_2S$ through time. However, P sampler was more stable to store $SO_2$ unlike others. Despite slightly reduced recovery, P sampler appears as a good replacement of T sampler.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.38-50
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• 2002

To study the distribution of organophosphorus pesticides which are extensively used for agriculture in Korea. Surface sea water samples were taken from 2 coastal areas during July and :;eptember of 1999 and sediment samples were collected from Kyeonggi bay in July of 1999. These samples were analyzed using a Gas Chromatography/Nitrogen Phosphorus Detector(GC/NPD). In coastal waters of the study areas IBP was commonly found the most compound. Traces of Diazinon, DDVP, Ethoprouhos and Chlorpyrifos were also encountered. Concentration of the other major organophosphorus pesticides(Disulfoton, Parathion Methyl, Fenchlorfos, Prothiofos, EDDP) were generally be below the detection limit of the employed analytical method. Tn sediment of the study areas Chlorpyrifos w3s found the most compound. Temporal and geographical distribution of individual organophosphorus pesticides is likely to be affected by types of agricultural practices in the watershed.

• Analytical Science and Technology
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• v.16 no.3
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• pp.240-248
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• 2003

Sulfur compounds which are well-known odor-active compounds in industrial area have very low detection threshold values. Trace amounts of volatile sulfur compounds in enviroment air around several odor sources were concentrated in liquid argon bath and determined by gas chromatograph with flame photometric detector (FPD) which exhibits very good selectivity and sensitivity. 25% ${\beta}$,${\beta}$-Oxydipropionitrile on 60/80 Chromosorb W was used as adsorbent for the preconcentration of sulfur compounds in air sample and also as packing material for a packed glass column. Concentration volume of air sample was different from place to place in the range of 0.1~3.0L. Atmospheric concentrations of sulfur compounds in air of residential districts and boundaries of business establishments, and also those in the exhausted gases of emission points such as a sewage disposal plant in industrial area were measured.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.475-475
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• 2010

We have generated Ar plasma in dense plasma focus device with coaxial electrodes for extreme ultraviolet (EUV) lithography and investigated an emitted visible light for electro-optical plasma diagnostics. We have applied an input voltage 4.5 kV to the capacitor bank of 1.53 uF and the diode chamber has been filled with Ar gas of pressure 8 mTorr. The inner surface of the cylindrical cathode has been attatched by an acetal insulator. Also, the anode made of tin metal. If we assumed that the focused plasma regions satisfy the local thermodynamic equilibrium (LTE) conditions, the electron temperature and density of the coaxial plasma focus could be obtained by Stark broadening of optical emission spectroscopy (OES). The Lorentzian profile for emission lines of Ar I of 426.629 nm and Ar II of 487.99 nm were measured with a visible monochromator. And the electron density has been estimated by FWHM (Full Width Half Maximum) of its profile. To find the exact value of FWHM, we observed the instrument line broadening of the monochromator with a Hg-Ar reference lamp. The electron temperature has been calculated using the two relative electron density ratios of the Stark profiles. In case of electron density, it has been observed by the Stark broadening method. This experiment result shows the temporal behavior of the electron temperature and density characteristics for the focused plasma. The EUV emission signal whose wavelength is about 6 ~ 16 nm has been detected by using a photo-detector (AXUV-100 Zr/C, IRD). The result compared the electron temperature and density with the temporal EUV signal. The electron density and temperature were observed to be $10^{16}\;cm^{-3}$ and 20 ~ 30 eV, respectively.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.721-727
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• 1998

An analytical method for simultaneous and rapid determination of organophosphorus, organochlorine, carbamate, and pyrethroid pesticides in polished rice was developed. The analysis is performed by gas chromatograph with mass selective detector (GC/MSD) in selected ion monitoring (SIM) mode. Pesticides were extracted from samples with acetone by automated Soxhlet apparatus and this extract was evaporated to dryness for the analysis. The residue was dissolved in hexane, followed by a treatment with a Sep-Pak florisil catridge. Pesticides were positively confirmed by GC/MS, retention times, and ion ratios. This analytical method allows a rapid, reliable, and a good recovery of hydrophilic pesticides. Except far captafol, captan, dichlofluanid and dichlorvos, recoveries of 42 pesticides were over 70%.

• Journal of Radiation Industry
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• v.3 no.1
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• pp.19-24
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• 2009

The citrus fruits were irradiated at different doses (25~200 kGy) to remove pesticides such as diuron, dichlorbenil, trifluralin, dimetoate, chlorothalonil, fenitrothion, bromacil, phenthoate and norflurazon, and the rates of degradation were detected by using gas chromatography electron capture detector (GC-ECD). The limit of detection (LOD) was in the range of 0.007~0.105 ppm. The limit of quantification (LOQ) was in the range of 0.024~0.352 ppm, and the recoveries of 9 pesticides were in the range of 71.5~106.5%. The results demonstrated that the ${\gamma}$-irradiation was effective method to remove pesticides such as diuron, dichlorbenil, trifluralin, dimetoate, chlorothalonil, fenitrothion, and norflurazon. However, the bromacil and phenthoate showed lower removal rates in the rate of 40.5 and 54.8%, respectively, at 200 kGy irradiation.